"Three terrorists infiltrated from Sinai into Israel and opened fire towards IDF soldiers guarding the border. The terrorists were well armed and carried explosive belts upon their bodies," she added.

Lt Leibovich said she did not have any information on the identity or affiliation of the gunmen. Previous attacks were blamed on Palestinian militants from the Gaza Strip and their supporters, who have allegedly established bases in the Sinai.

An Egyptian security source said one of the gunmen died when a bomb he was carrying detonated and the other two were killed in a gun battle with Israeli forces. He added that the nationalities of the gunmen were not immediately clear.

In August, Islamist militants killed 16 Egyptian border guards and commandeered an armoured vehicle which they smashed across the border before being killed by the Israeli military.

In June, militants crossed the border area and fired on Israelis building a barrier along the desert frontier, killing a worker, before soldiers shot dead two of the attackers.

Israel is putting up the border fence to curb an influx of African migrants and improve security, hoping to complete it by the end of the year. It will run along most of the 266-km (165 miles) frontier from Eilat, on the Red Sea, to the Gaza Strip.

Lt Leibovich said today's attack took place about halfway down the desolate border near an area known as Mount Harif, where the barrier is still under construction.

Egypt launched a crackdown on lawlessness in the Sinai following the Aug. 6 massacre and has sent additional forces into the area.